Battery Inversion? Starter Solenoid/Motor?

Weird Problem:
ACC and ON positions: all electrical systems work normally
START: All power is lost to the vehicle and there is a loud 'snick' sound from the engine bay

battery voltage is 12.7 at OFF,ACC, and ON
after START->ON battery voltage is 12.7 still, but when measured between the negative terminal and the chassis reads -12.7 (as if the positive lead is shorted to the chassis)

if there were a short, I would expect the starter fuse to have blown the first time and not have been repeatable. As it stands, after the power loss, a softer snick is heard ~30 seconds later and the system returns to normal ACC and ON operation.

My thought right now is fried starter motor. Any troubleshooting ideas? As always, thanks in advance for the help.

Loose battery cable or ground connection would be the 1st place I would look.
Battery is shorting out internally... bad battery. Remove and take to local parts store and have load tested.

I1 :)

Spoke with my brother (former mechanic, former honda salesman, all-around handy-guy) and he had a similar problem with his CRX back a few months ago. (ended up being a loose ground) So I guess that's where I will start tomorrow afternoon.

FIXED!

It was a bad connection at the neg. post (which meant that when the starter kicked on sufficient current couldn't flow to the negative post, but was welling up voltage just of the other side of the disconnect. Hence, the battery voltage between the post and the cable/chassis...